Physical properties:
Color: Red to dark brown (black if altered)
Luster: Glassy to dull
Hardness: 6 - 7.5
Specific Gravity: 3.5
Usually as either smooth, dark red gemmy crystals showing basically the trapezohedral form; sometimes modified by the dodecahedral form; rarely as octahedral crystals or as highly modified "clinkers" made up of basically garnet inter-grown with either rhyolite and/or quartz. They also occurs as pseudomorphs; hematite being the most common mineral replacing the garnet. Often the garnets consist of a thin altered rind on the outside and pure unaltered garnet in the center. In size, most are under ½" (12mm) in diameter, but may form crystals exceeding 2.5" (6.5cm) in diameter; the largest gemmy crystal was 2.2" (5.5cm) in diameter. They may form as single crystals or as clusters consisting of several dozen individual crystals.
Garnets are another mineral of interest to collectors. They occur throughout the Thomas Range in isolated areas. They also occur in two types. One type consists of euhedral crystals, with the most common forms being the basic trapezohedron, sometimes modified by the dodecahedron. These crystals seldom exceed 0.5" in diameter, although, crystals exceeding two inches in diameter have been found.
In color, they vary from brown to a deep cinnamon-red color. They are sometimes well formed, smooth-faced crystals, often of gem quality. Mostly they contain minute inclusions of quartz, topaz and hematite and have a sugary texture similar to the sand topaz. As topaz also occurs in the area, it is not uncommon to find good combinations of the two.
Type I can be found in several places in the range, most notably at "Garnet Basin" Type II consists of small rounded opaque crystals; some show the basic trapezohedral faces while others are nothing more than massive "Clinkers," resembling the clinkers from furnaces. They are usually altered, consisting of an outer core made up of hematite, quartz and topaz and an inner core of unaltered garnet ( the composition is halfway between spessartine and almandine). Sometimes they consist merely of an unaltered red rind made up of garnet, quartz and topaz. They occur in both the lithophysal cavities and in solid rhyolite.
At one locality north of Topaz Mountain (Maynard Topaz Mine), there is an occurrence of Type II garnets in cluster form with bixbyite crystals perched all over the surfaces.
